Several trends presently exist in the semiconductor and electronics industry. One of these trends is that recent generations of portable electronic devices are using more memory than previous generations. This increase in memory allows these new devices to store more data, such as music or images, and also provides the devices with more computational power and speed.
Dynamic random access memory (DRAM) is one type of random access memory where individual bits of data are stored in separate capacitors arranged in an array-like manner. In FIG. 1, one can see a somewhat conventional DRAM memory array 100 that includes a number of memory cells 102, each of which includes a capacitor (e.g., 104) that is accessible via an access transistor (e.g., 106). The memory cells 102 are arranged in M rows (e.g., words) and N columns (e.g., bits). Each row of memory cells is an N bit data word accessible by activation of a wordline WL that is coupled to the access transistors of that row.
Because the capacitors leak charge, any data stored in the memory cells will fade unless it is refreshed periodically. Because of this characteristic, a DRAM is a dynamic memory, as opposed to SRAM and other types of static memory. When compared to SRAM, one advantage of DRAM is that it can have very high densities because of its simplistic memory cell structure.
Therefore, in many arenas when a large amount of data storage is desired, DRAM is often a relatively affordable solution. While existing types of DRAM are sufficient for their stated purpose, it would be useful to have new types of DRAM, particularly as new process technologies and devices emerge.